Firefox fork for Linux?

I’m looking for a lightweight fork of Firefox, because this browser is eating up my netbook’s RAM like nothing good. Firefox was really awesome until two or three versions ago; and I don’t really want to switch to a completely different browser (though I’ll give Midori a try). Any suggestions would be more than welcome!

I’m using a Lenovo Ideapad S10-3, the current operating system is Linux, Ubuntu 12.04.4 (LTS); might be upgraded to next Long Term Support version sometime this or next year.

The Author

I'm living in dreams of late summer warmth and happiness in aromatic meadows and golden fields, I'm living the life of a university student in a big European city in the north, I'm dreaming of a way of life I can't describe yet.